1. Field of the Invention
This invention relates to a battery pack charging device for charging a battery pack which is loaded on a potable electronic equipment for supplying the DC power thereto.
2. Description of Related Art
A battery pack charging device has a battery pack loading unit, formed as a recess on e.g., a major surface of a casing of the device, for charging the battery pack loaded therein. In general, the battery pack charging device includes a DC power supply circuit, and a current detection circuit, or a control circuit, enclosed in a housing, and also includes, in the battery loading section, a charging electrode terminal member for connection to a charging terminal member of the battery pack, and a communication terminal for exchanging the information with the battery pack. The battery loading section of the battery pack charging device is provided with a detection switch for detecting the loading of the battery pack. When the loading of the battery pack into the battery loading section has been confirmed by the detection switch, the DC current is supplied from the DC power supply to the charging electrode for charging the battery pack.
In general, a lock mechanism for holding the loaded state of the battery pack and a popup mechanism for hoisting the battery pack from within the battery pack holding section are provided in the battery pack loading unit of the battery pack charging device. The lock mechanism includes a lock member including a lock part formed at the foremost part thereof and which is slidably mounted in the casing so as to be biased to be protruded into the battery pack loading unit. When the battery pack is loaded in the battery pack loading unit, the lock part of the lock member is engaged in a lock recess formed in the battery pack to keep the loaded state.
The role of the popup mechanism is usually simultaneously performed by an electrode terminal member connected to the charging terminal member of the battery pack. For example, the free end of the electrode terminal member, formed by e.g., a plate spring, is projected into the battery pack loading unit. In the popup mechanism, when the battery pack is loaded in the battery pack loading unit, the electrode terminal member is connected to a charging terminal member of the battery pack and is thrust by the battery pack to accumulate the force of elasticity. When the charging operation comes to a close and the lock mechanism is actuated, the popup mechanism lifts the battery pack by the force of elasticity to facilitate removal of the battery pack from the battery pack loading unit.
In the above-described battery pack charging device, since the electrode terminal member simultaneously performs the role of the popup mechanism, the shape-related degree of freedom of the charging electrode unit, inclusive of the electrode terminal member, is limited by the structure of the battery pack side charging terminal unit. The conventional battery pack charging device suffers from the drawback that it must be constructed with different structures of the battery pack loading unit, lock mechanism or the charging electrode unit, in keeping with design parameters for outer shapes of the battery pack or design parameters of the charging terminal unit, which design parameters may be variegated depending on the design parameters of the electronic equipment. As a consequence, the conventional battery pack charging device lacks in universality.
Moreover, in the battery pack charging device, respective terminals of the charging terminal unit are reduced in pitch, in keeping with attempts in reducing the size and thickness of electronic equipment, consequent upon the improved performance of the secondary cell, so that the terminals of the charging terminal unit are also reduced in pitch. The conventional battery pack charging device has a drawback that, since each electrode terminal member is usually constructed by a plate spring, which plate spring must be afforded with the function of accumulating sufficient force of elasticity to hoist the battery pack, it is difficult to reduce the size of the battery pack charging device.
Moreover, in the conventional battery pack charging device, each electrode terminal member, formed by a plate spring to perform the popup function, is mounted as it is protruded into the inside of the battery pack loading unit. If, in the battery pack charging device, the battery pack is placed within the battery pack loading unit but is not being charged, the electrode terminal member and the electrode terminal member facing each other need to be kept in the non-connected state in order to prevent e.g., overcharging to maintain safety. If, in the battery pack charging device, burrs are produced or acute protrusions are encountered on the outer periphery of each electrode terminal member, formed by a plate spring, there is raised such a problem that these burrs or protrusions interfere with the guide holes in the casing to produce malfunctions or electrical shorting, or with the operator""s fingers during operation or handling.
In order to overcome the above problems, encountered with the battery pack charging device, it may be contemplated to maintain non-conducting states for the respective electrode terminal members or to use a molded cover member for overlying the outer periphery of the battery pack charging device. This solution is difficult to resort to because the respective electrode terminal members are directly contacted with the respective charging terminal members. With the conventional battery pack charging device, it is necessary to take such measures as removing the burrs produced on the outer periphery, or to chamfer the protrusions, by way of post-processing. The necessity of taking these measures as well as the shape-related restrictions accounts for increased costs of the battery pack charging device.
It is therefore an object of the present invention to provide a battery pack charging device in which the structure-related degree of freedom imposed by the charging terminal unit of the battery pack, as well as safety and reliability, may be improved, and in which the demand for reduction in size and cost of the device is met.
The present invention provides a battery pack charging device in which a battery pack, including a charging terminal unit arranged on a first lateral surface and a mating lock portion on a second lateral surface opposite to the first lateral surface, is loaded in a battery pack loading unit formed as a recess in a major surface of a device casing, from the first lateral surface. The battery pack charging device includes a charging electrode unit arranged on a first lateral surface section of the battery pack loading unit, to which the first lateral surface of the battery pack is abutted, the charging electrode unit being connected to the charging terminal unit of the loaded battery pack, a holder provided to the first lateral surface section of the battery pack loading unit for holding the first lateral surface of the loaded battery pack, a lock member provided on a second lateral surface section opposite to the first lateral surface section of the battery pack loading unit and slidably mounted to the major surface of the device casing, the lock member including a lock portion engaged with the mating lock portion of the loaded battery pack, and an ejection member having one end rotatably carried by a support formed in an inner surface of the device casing and having its other end facing a guide opening formed in the bottom surface of the second lateral surface section of the battery pack loading unit, the ejection member being biased to be intruded into the guide opening.
In the present battery pack charging device, the ejection member is thrust by the battery pack loaded into the battery pack loading unit, so that an elastic force is accumulated in the ejection member. The first lateral surface of the battery pack is held by the holder in this state, while the lock member locks the mating lock portion of the second lateral surface to accommodate the battery pack. When the charging operation comes to a close, the lock member is slid to unlock the mating lock portion from the lock portion, while the ejection member is uplifted from the bottom surface of the battery pack loading unit under the elastic force stored.
In the present battery pack charging device, in which the battery pack loaded in the battery pack loading unit is reliably uplifted by the ejection member, the charging electrode unit can be constructed with a relatively free shape not restricted by the shape of the charging terminal member of the battery pack, thus assuring universality. In the present battery pack charging device, the charging electrode members of the charging electrode unit can be reduced in pitch and size, in keeping with the reduction in size and pitch of the charging terminal members of the battery pack, thus reducing the size of the device. Moreover, the charging electrode members and the charging terminal members can be reliably connected to one another without the risk of erroneous connection, thus improving reliability. Additionally, the post-processing, such as deburring, can be omitted, thus further reducing the production cost.
In the present battery pack charging device, including the ejection member thrust by the battery pack loaded in the battery pack loading unit to accumulate the elastic force therein, and the lock member engaged with the mating lock portion to hold the battery pack in the battery pack loading unit, the locked state by the lock member is annulled, on completion of the charging operation, to uplift the battery pack from the battery pack loading unit, so that the charging electrode unit can be designed to free shape without being restricted by the shape of the charting terminal unit, thus achieving universality. With the present battery pack charging device, the pitch and size of the charging electrode unit and the charting terminal unit can be reduced, while the overall device may also be reduced in size. Moreover, the charging electrode unit and the charging terminal unit mating therewith can be reliably connected to one another, without the risk of erroneous connection, thus improving operational reliability. Additionally, post-processing such as deburring of the respective charging electrode members can be omitted to achieve further reduction in production cost.